Traveling wave-based setting free fault location for transmission lines using unsynchronized data

A method is proposed for locating fault on two-terminal transmission lines using traveling-waves from two-ended unsynchronized current measurements. It considers the line length to be divided into four zones and computes per unit fault locations assuming the fault to be present in each of these zones separately. It then estimates the faulted zone, and the corresponding fault location estimate is displayed as the final output. These computations involve measuring three travelling wave arrivals at each terminal. The method is free of wave speed (or line parameter) input and is inherently immune to data synchronization issues. The method can work satisfactorily even when current measurements from both the ends are not properly synchronized. It is tested on a 200 km transmission line simulated in PSCAD/EMTDC. It works satisfactorily for various fault scenarios and is robust to errors in wave speed and data synchronization errors. The performance is also compared with a classical two–terminal method.